To make the output voltage of a laser power monitor circuit (12) equal to a predetermined value at a predetermined laser power, adjustment is performed by changing an external variable resistance for output voltage adjustment. To achieve this, adjustment is performed by changing the variable resistance so that the difference between a high level output pulse of the laser power monitor circuit (12) obtained when an LD (11) is turned off and a low level output pulse obtained when the LD (11) is turned on is made equal to a target adjusted voltage. This prevents the offset of the laser power monitor circuit (12) from affecting a monitor output voltage, allowing an optical pickup to perform, for example, recording and reproducing with higher accuracy.